Carbon monoxide (CO) is a colourless, odourless, invisible, and very toxic gas. It is the product of incomplete combustion. If a carbon-based fuel, such as petrol, wood, coal or charcoal briquettes, is burned in an atmosphere with insufficient oxygen, the carbon in the fuel is not completely oxidised into carbon dioxide, and carbon monoxide results.
Hazard detectors and alarms which contain CO sensors are used in both the domestic and the industrial sectors. The CO sensors/detectors monitor the atmosphere for the presence of a build up of CO, which might be the consequence of a faulty gas heater or a slow-burning fire.
Over a period of time, the CO sensors deteriorate. In order to verify the performance of the sensor and the correct operation of any hazard detector or alarm containing a CO sensor, periodic tests need to be carried out on them. To perform such a test, a small amount of CO needs to be introduced into the sensor/detector in a concentration that is large enough to activate the sensor/detector into an alarm mode, but small enough, such that if it were released into the atmosphere, it would be within safe limits and pose no risk to human health.
Currently there are a variety of methods for testing CO sensors in hazard detectors. These include the use of small glass vials of CO which are broken in the presence of the sensor/detector, smouldering Incense Sticks or using a dilute mixture of carbon monoxide gas mixed with air, nitrogen or another inert gas. In the latter case, the gas is usually stored in a pressurised cylinder or in an aerosol can. One such CO aerosol can tester is sold under the trade name Solo CO™.
These methods are either not convenient, or are considered dangerous. The use of glass vials can be dangerous, as a new glass vial must be broken each time a test is carried out. Plus the CO contained in such vials is generally very concentrated and therefore poses a risk to human health. In the case of smouldering Incense Sticks, a naked flame must be used for ignition, a significant odour is produced and they do not lend themselves to applications where repeated tests are required throughout a prolonged working period. In addition, the use of pressurised containers is not convenient as they are often heavy and bulky and they are classified as hazardous, hence costly to transport. Since a large amount of the gas can be stored in larger containers, and the gas itself is odourless, it can be dangerous or even fatal if the contents are released in a confined unventilated space.
Other current methods for producing CO (usually on a commercial scale) are too large to be scaled down, and the production of CO by the chemical reaction of hazardous chemicals is deemed too dangerous to incorporate into a portable appliance.
It is an object of the present invention to address the above-identified problems and to provide a safe and easy to way to generate CO that can then be utilised in a sensor/detector tester.
It is a further object of the present invention to provide a portable CO sensor/detector tester.
It is a further object of the present invention to provide a CO sensor/detector tester which utilises non-hazardous materials and/or chemicals.